In advanced counties, a great deal of effort has been concentrated on safe vehicle operation using various kinds of speed meters operating with different microwave frequencies and lasers, and using transmitters for the purpose of prior safety alarm that inform various hazardous road situations. Especially in the United States of America, such speed meters and detectors are legally approved.
Types of signals used in such meters and detectors depend on the equipments in use and they are as follows.
In other words, speed guns preventing vehicle over-speeding utilize X-band (10.525 GHz), Ku-band (13.450 GHz), K-band (24.150 GHz), superwide Ka-band (diversely distributed between 33.000 GHz and 36.000 GHz), and the lasers (having wavelengths between 800 nm and 1100 nm); safety alert systems providing road information for safe vehicle operation utilize frequencies between 24.070 GHz and 24.230 GHz and transmit three information that are “railroad crossing,” “under construction,” and “emergency vehicle”; and safety warning systems utilize frequencies between 24.075 GHz and 24.125 GHz and transmit 64 kinds of coded information including “foggy area,” “under construction,” “school zone,” “reduced speed,” and the like.
Above mentioned safety related transceiver systems are currently revitalized in and around the United States of America, and are expanding globally, and expected to be highly interrelated with the future intelligent transportation system (ITS).
All the above mentioned frequencies and usage thereof are regulated by the Federal Communication Commission (FCC) of the United States of America.
FIG. 1 illustrates conventional broadband radar detector. As shown in FIG. 1, the broadband radar detector is comprised of: a horn antenna 10; a signal processing unit 20 detecting signal received by the horn antenna 10; a laser module 30 receiving laser signal; a central processing unit 40 controlling signal detection from the signal processing unit 20 and the laser module 30; a visualizing means 50 visually displaying the detected signals; and a voice means 60 presenting the detected signals as a voice via voice amplification unit 61; and, receives signals at 9 frequency bands including X, VG2, Ku, K, SA, SWS, superwide Ka, and laser, and outputs received signals in a best-fit manner corresponding to the user's situation thereby assisting the user on safety vehicle operation.
Besides, since conventional MMIC based wideband radar detectors receive frequencies between 24 GHz and 36 GHz therefore Ka band frequencies can be detected, however, the X-band, VG2-band and Ku-band frequencies cannot be detected. Thus, there is a need for a wideband frequency detector that can detect wideband frequencies while using MMICs therein.